1. Field of the Invention
The present invention relates to a multilayer ceramic capacitor.
2. Description of the Related Art
The reduction in size and the reduction in thickness have been further progressed for electronic devices as typified by cellular phones and the like. In response to the current situation, the reduction in size and the reduction in thickness have been also progressed for multilayer ceramic capacitors included in the electronic devices. The multilayer ceramic capacitors each include, for example: a laminated body formed in a rectangular parallelepiped shape by alternately laminating ceramic layers for inner layers and internal electrode layers, and further laminating ceramic layers for outer layers on each of principal surfaces opposite to each other in the laminating direction; and external electrodes formed on each of end surfaces opposite to each other in the length direction of the laminated body. Japanese Patent Application Laid-Open No. 2002-353068 discloses a multilayer ceramic capacitor for purposes such as arranging a product shape into a rectangular parallelepiped.
The multilayer ceramic capacitor in Japanese Patent Application Laid-Open No. 2002-353068 is composed of dielectric layers of a sintered body such as a ceramic, first internal electrode layers, second internal electrode layers, and external electrode layers. The laminated body is, in the direction along principal surfaces of the laminate, classified into: portions where the internal electrodes are not adjacent closest to each other in the laminating direction (end surface parts); and a portion where the internal electrodes are adjacent closest to each other therein (a central portion sandwiched between the respective end surface portions). In this regard, the second internal electrode layers refer to internal electrode layers formed by lamination at the end surface portions over the first internal electrode layers. The internal electrode thicknesses at the end surface portions (the thickness of the first internal electrode layer+the thickness of the second internal electrode layer) are larger than the internal electrode thickness (the thickness of the first internal electrode layer) at the central portion.
The multilayer ceramic capacitor in Japanese Patent Application Laid-Open No. 2002-353068 includes the external electrodes on each of end surfaces of the laminated body. These external electrodes are typically formed by applying a conductive paste to the end surfaces of the laminated body, and sintering the paste. The conductive paste diffuses into the internal electrode layers in the process of being sintered. Thus, portions of the internal electrode layers (portions located closer to the end surfaces of the laminated body) are bloated, thus generating deflection stress in the laminated body. As a result, the multilayer ceramic capacitor has the problem of being cracked. In particular, in the multilayer ceramic capacitor in Japanese Patent Application Laid-Open No. 2002-353068, this problem occurs frequently and is significant because the internal electrode layers located closer to the end surfaces are large in a thickness dimension.